The present invention relates to a device for performing endoscopic guided fine-needle biopsy.
In the medicine it is known that, to collect a tissue sample, a hollow needle is used to puncture tissue and to gain biological material for histological, cytological or genetechnological examinations.
As to the cytological examination, in particular, fine-needle biopsy is known. In this biopsy, cell material is collected by a thin hollow needle by means of suction. Usually the collection of the tissues and the positioning of the hollow needle are monitored with ultrasonic waves. The monitoring by the use of ultrasonic waves is necessary, particularly when it is necessary to collect the tissue from a small region which has been specified.
In case of percutaneous hollow-needle biopsy, the needle is pushed forward through the skin of the patient until it reaches the tissue from which a sample shall be collected. The percutaneous hollow-needle biopsy is suitable for collecting tissue which can be easily accessed, directly through the skin. Ordinary needles have a length of 6 to 10 cm and are monitored by means of an imaging method, such as ultrasonic or computer tomography. The efficiency of the tissue sampling and the efficiency of penetrating hardened tissue can be improved by abruptly pushing the needle if the needle is relatively short. The pushing of the needle can be assisted by a spring force.
Certain tissues are not suitable for being punctured with a percutaneous biopsy needle. This is because the needle cannot reach the tissue. For example, another tissue can block the insertion of the biopsy needle.
Hereto it has been known that a biopsy needle can also be guided through an echo-endoscope, to thereby collect tissues through a hollow organ (Hahlorgan). In this technique, the echo-endoscope possess not only functions as an optical monitor for the puncture, but also is a protecting sleeve and a means for guiding the needle over a long distance and positioning the needle at the sampling position.
The technique of echo-endoscopic fine-needle biopsy is employed to, for example, collect pancreasor lymphatic node tissue. The echo-endoscope which is appropriate for use in this technique has a passage for guiding the biopsy needle. The needle is inserted into the hollow organ, while being guided through the echo-endoscope, until it reaches the sampling position. At the sampling position, the needle is inserted into the tissue and moved back and forth, whereby a sample is separated from the tissue by virtue of a negative pressure. In order to obtain material in a sufficient amount for cytological or histological examination, the needle must be moved back and forth many times.
In this technique, the needle needs to be long enough to have access to the tissue to be sampled, through a hollow organ. This results in some drawbacks. The length of the needle must be greater than the length of the endoscope. For example, tissues must be sampled with needles about 160 cm long, or ten times or more as long as needles for use in percutaneous biopsy.
Some skill is required to operate endoscopes. For example, it is difficult to control the needle in the grip region of an endoscope, in the process of positioning an endoscope. This is true, especially when the needle must be guided along several curves, through a passage formed in the endoscope. The force which is necessary for moving the needle increases as the needle is guided along each curve, due to the frictional forces at the curves. The sum of the frictional forces may become considerable. The user must manually overcome the sum of frictional forces. This makes it difficult to perform a precise operation, causes the danger of breaking the needle, and may result in damage to the echo-endoscope which is a sensitive component.
In addition, the fine needle biopsy relating to echo-endosonography cannot be achieved at all when the tissue to be sampled has a certain hardness, as do pathologically hardened tissues. In this case, the needle is not inserted into the tissue. If the needle is inserted, the pressure applied to it will increase very much. Even in the best case, the needle or the endoscope connected to the needle may avoid contacting the tissue, but the endoscope may nevertheless be damaged.
Even if the tissue is easy to penetrate, the tissue sampled is often not satisfactory. This is especially disadvantageous, when the punctured tissue is intended for a cytlogical or histological examination. Thus, the biopsy needle must be moved back and forth several times to increase the amount of tissue sampled. Even if this technique is applied, it may not possible to sample tissue in a useful amount.